Obstruction of the urinary tract can increase pelvi-ureteric pressure and thus cause renal colic pain, which can be very severe. Conventional therapy consists of non-steroidal anti-inflammatory drugs (NSAIDs) and opioids. NSAIDs have many side effects and opioids are not always available. In addition, the intravenous form of NSAIDs is not routinely available in Iran, and the drug is mainly used in the form of suppository. Due to these reasons, research on newer replacement therapies with fewer side effects is necessary. Desmopressin intranasal spray has already been shown to be partially effective in renal colic pain in a few studies. Due to its lower side effects, we decided to conduct a clinical trial with desmopressin to evaluate pain relief in renal colic. In this study, eighty-eight patients with acute renal colic pain, referring to Imam Khomeini Hospital in Tehran, will be randomly allocated to receive either intranasal desmopressin or placebo. Both groups will also receive 100 milligram indomethacin suppository. Pain intensity will be assessed and recorded using a verbal numeric rating scale, before nasal spray, and in minutes 5, 10, 15, 30, 45 and 60 after receiving the allocated treatment. Possible side effects will also be asked and recorded. The patient and the investigator responsible for recording pain intensity will not be aware of the administered drug. The results will be compared before and after treatment in each group, using appropriate statistical tests.